Ether Channel is an Ethernet technology described in the Institute for Electrical and Electronic Engineers (IEEE) specification IEEE 802.3ad. Ether Channel aggregates multiple point-to-point physical ports into a single logical port. Ether Channel provides load balancing of different data flows across different physical data links, achieving higher aggregate bandwidth. Ether Channel also provides link level resiliency, where the use of multiple physical data links enables continued data flows across a logical link even if one of the physical data links encounters a failure. However, Ether Channel technology is limited only between two physical devices.
A multi-chassis Ether Channel (MCEC) interface can span more than one physical switch, where physical data links that are physically connected to different switching device chassis can be viewed as a single Ether Channel. An example MCEC-based switching system is the commercially available Cisco Catalyst 6500 Series Virtual Switching System 1440 from Cisco Systems, San Jose Calif.
First hop redundancy protocols (FHRP) can provide default gateway redundancy for host network devices, where two or more router devices negotiate to identify one router as a single active gateway device, and a second router as single standby gateway device. Example FHRP protocols include the Hot Standby Router Protocol (HSRP) described in the Internet Engineering Task Force (IETF) Request for Comments (RFC) 2281, the Virtual Router Redundancy Protocol (VRRP) described in the IETF RFC 3768, and the Gateway Load-Balancing Protocol (GLBP) that is commercially available from Cisco Systems, San Jose Calif.